Hondo Group
| Hondo Group | |
|---|---|
| Stratigraphic range: | |
 Hondo Group (Ortega Formation) in the Tusas Mountains, New Mexico | |
| Type | Group |
| Sub-units | Ortega Formation, Rinconada Formation |
| Underlies | Pilar Formation |
| Overlies | Vadito Group |
| Thickness | 2,200 m (7,200 ft) |
| Lithology | |
| Primary | Metasedimentary rock |
| Location | |
| Coordinates | 36°14′46″N 105°44′42″W / 36.246°N 105.745°W |
| Region | Picuris Mountains, New Mexico |
| Country | United States |
| Type section | |
| Named for | Hondo Canyon |
| Named by | Bauer and Williams |
| Year defined | 1989 |
  Hondo Group (New Mexico) Map of Hondo Group outcrops | |
The Hondo Group is a
Geology
The Hondo Group consists of a lower very clean
The
The Hondo Group lies structurally below the Vadito Group in the Picuris Mountains. However, both groups have been severely deformed and metamorphosed, and the Vadito Group is thought to actually be the older of the two groups. Cross-bedding indicates that the Vadito Group has been overturned.[5] The contact between the two groups is fairly easy to trace using a regional manganese-rich marker bed in the uppermost Vadito Group,[2] which may have formed by syngenetic deposition from hydrothermal fluids, or a more general manganese enrichment of basin waters at the close of Vadito volcanism. Another possibility is that it is a weathering horizon. Either possibility would make it an important regional time marker.[6]
The group is interpreted as
Economic geology
Gold, silver, and oxidized copper minerals were discovered on Copper Hill around 1900 and prospected over the next five years. The ore minerals were concentrated along the contact between the Ortega and Rinconada Formations. Mining began along the Champion vein on the west side of the hill, with two shaft connected by an adit 100 meters (330 feet) long. However, the mine was unsuccessful. Renewed exploratory drilling in 1982 determined that the deposits are presently uneconomical to mine.[7]
History of investigation
The unit was originally designated as the Ortega Group by Long in 1976, but this caused confusion with the Ortega Formation. The name, Hondo Group, was proposed by Bauer and Williams in 1989 as part of their sweeping revision of the Precambrian stratigraphy of northern New Mexico.[2]
Footnotes
References
- Bauer, Paul W. (2004). "Proterozoic rocks of the Pilar Cliffs, Picuris Mountains, New Mexico" (PDF). New Mexico Geological Society Field Conference Series. 55: 193–205. Retrieved 15 April 2020.
- Bauer, Paul W.; Williams, Michael L. (August 1989). "Stratigraphic nomenclature ol proterozoic rocks, northern New Mexico-revisions, redefinitions, and formalization" (PDF). New Mexico Geology. 11 (3). Retrieved 15 April 2020.
- Daniel, Christopher G.; Pfeifer, Lily S.; Jones, James V III; McFarlane, Christopher M. (2013). "Detrital zircon evidence for non-Laurentian provenance, Mesoproterozoic (ca. 1490–1450 Ma) deposition and orogenesis in a reconstructed orogenic belt, northern New Mexico, USA: Defining the Picuris orogeny". GSA Bulletin. 125 (9–10): 1423–1441. doi:10.1130/B30804.1. Retrieved 17 April 2020.
- Jones, James V. III; Daniel, Christopher G.; Frei, Dirk; Thrane, Kristine (2011). "Revised regional correlations and tectonic implications of Paleoproterozoic and Mesoproterozoic metasedimentary rocks in northern New Mexico, USA: New findings from detrital zircon studies of the Hondo Group, Vadito Group, and Marqueñas Formation". Geosphere. 7 (4): 974–991. . Retrieved 15 April 2020.
- Montgomery, Arthur (1953). "PreCambrian Geology of the Picuris Range, northcentral New Mexico" (PDF). State Bureau of Mines and Mineral Resources Bulletins. 30.
- Williams, M.L. (1987). Stratigraphic, structural, and metamorphic relationships in Proterozoic rocks from northern New Mexico [Ph.D. dissertation]:. Albuquerque: University of New Mexico.
- Williams, Michael L.; Bauer, Paul W. (1 November 1995). "The Copper Hill Cu-Ag-Sb deposit, Picuris Range, New Mexico; retrograde mineralization in a brittle-ductile trap". Economic Geology. 90 (7): 1994–2005. .